This CL prevents redundancy elimination from widening types, which
can cause problems if the input of a DeadValue (which has type None)
is replaced by an equivalent node that does not have type None. This
can happen because load elimination does not re-type nodes, for
example.

Bug: chromium:919340
Change-Id: I89e872412edbcdc610e70ae160cde56cd045006c
Reviewed-on: https://chromium-review.googlesource.com/c/1397709Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58617}